A Manhattan plastic surgeon who is a pal of former NYPD Commissioner Bill Bratton is using his police parking placard to leave his Mercedes-Benz SUV in front of fire hydrants on his E. 57th Street block, sources told The Post.

A neighbor said the doctor, R. Richard Leinhardt, allegedly used police lights and sirens that are active in his car to try and make a doorman move his car from in front of the hydrant three weeks ago.

The doorman at 440 E. 57th St., who only gave his name as Martin, said Leinhardt “was trying to pretend he was a cop.”

Leinhardt denied the claims and said he tries not to park by hydrants, but does so when he’s on call as a first responder.

Leinhardt, 69, who lives at 430 E. 57th St., is a former chief surgeon for the Transit Police, according to the bio on his medical practice website. He told The Post he also works for the NYPD.

A police spokesman said, “He works for us, but you still can’t park by a fire hydrant. It’s got to be within reason.

“The matter is under internal review,” said the spokesman, Lt. John Grimpel.

The Park Avenue surgeon has also done pro bono facial reconstructive work for cops.

The doorman said Leinhardt’s Mercedes is parked within hydrant zones most nights when he arrives for his 10 p.m. shift and remains there until the morning.

The permit does not allow holders to park in front of or near a hydrant, and is only supposed to be used when drivers are on official business.